|
Principle (chemistry)
Principle, in chemistry, refers to an historical concept of the constituents of a substance, specifically those that produce a certain quality or effect in the substance, such as a ''bitter principle'', which is any one of the numerous compounds having a bitter taste. The idea of chemical principles developed out of the classical elements. Paracelsus identified the ''tria prima'' as principles in his approach to medicine. Georg Ernst Stahl published ''Philosophical Principles of Universal Chemistry'' in 1730 as an early effort to distinguish between mixtures and compounds. He writes, "the ''simple'' are ''Principles'', or the first material causes of ''Mixts'';..." Georg Ernst Stahl (1730Philosophical Principles of Universal Chemistry Peter Shaw translator, from Open Library To define a Principle, he wrote :A Principle is defined, ''à priori'', that in a mix’d matter, which ''first existed''; and ''a posteriori'', that into which it is at ''last resolved''. (...) ''chemical P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taste
The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, mostly on the tongue. Taste, along with olfaction and trigeminal nerve stimulation (registering texture, pain, and temperature), determines flavors of food and other substances. Humans have taste receptors on taste buds and other areas, including the upper surface of the tongue and the epiglottis. The gustatory cortex is responsible for the perception of taste. The tongue is covered with thousands of small bumps called papillae, which are visible to the naked eye. Within each papilla are hundreds of taste buds. The exception to this is the filiform papillae that do not contain taste buds. There are between 2000 and 5000Boron, W.F., E.L. Boulpaep. 2003. Medical Physiology. 1st ed. Elsevi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Elements
Classical elements typically refer to earth, water, air, fire, and (later) aether which were proposed to explain the nature and complexity of all matter in terms of simpler substances. Ancient cultures in Greece, Tibet, and India had similar lists which sometimes referred, in local languages, to "air" as "wind" and the fifth element as "void". These different cultures and even individual philosophers had widely varying explanations concerning their attributes and how they related to observable phenomena as well as cosmology. Sometimes these theories overlapped with mythology and were personified in deities. Some of these interpretations included atomism (the idea of very small, indivisible portions of matter), but other interpretations considered the elements to be divisible into infinitely small pieces without changing their nature. While the classification of the material world in ancient Indian, Hellenistic Egypt, and ancient Greece into Air, Earth, Fire and Water wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracelsus
Paracelsus (; ; 1493 – 24 September 1541), born Theophrastus von Hohenheim (full name Philippus Aureolus Theophrastus Bombastus von Hohenheim), was a Swiss physician, alchemist, lay theologian, and philosopher of the German Renaissance. He was a pioneer in several aspects of the " medical revolution" of the Renaissance, emphasizing the value of observation in combination with received wisdom. He is credited as the "father of toxicology". Paracelsus also had a substantial influence as a prophet or diviner, his "Prognostications" being studied by Rosicrucians in the 1600s. Paracelsianism is the early modern medical movement inspired by the study of his works. Biography Paracelsus was born in Egg an der Sihl, a village close to the Etzel Pass in Einsiedeln, Schwyz. He was born in a house right next to a bridge across the Sihl river (known as ''Teufelsbrücke''). The historical house, dated to the 14th century, was destroyed in 1814. The ''Restaurant Krone'' now stands in it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georg Ernst Stahl
Georg Ernst Stahl (22 October 1659 – 24 May 1734) was a German chemist, physician and philosopher. He was a supporter of vitalism, and until the late 18th century his works on phlogiston were accepted as an explanation for chemical processes.Ku-ming Chang (2008)"Stahl, Georg Ernst", ''Complete Dictionary of Scientific Biography'', Vol. 24, from Cengage Learning __TOC__ Biography Georg Ernst Stahl was born on October 22, 1659, at Anspach in Bavaria. Raised as a son to a Lutheran Pastor, he was brought up in a very pious and religious household. From an early age he expressed profound interest toward chemistry, even by age 15 mastering a set of university lecture notes on chemistry and eventually a difficult treatise by Johann Kunckel. He had two wives, who both died from puerperal fever in 1696 and 1706. He also had a son Johnathan and a daughter who died in 1708. He continued to work and publish following the death of both of his wives and eventually his children, but was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixture
In chemistry, a mixture is a material made up of two or more different chemical substances which are not chemically bonded. A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids. Mixtures are one product of mechanically blending or mixing chemical substances such as elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup. Despite the fact that there are no chemical changes to its constituents, the physical properties of a mixture, such as its melting point, may differ from those of the components. Some mixtures can be separated into their components by using physical (mechanical or thermal) means. Azeotropes are one kind of mixture that usually poses considerable difficulties regarding the separation processes required to obtain their constituents (physical or chemic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound (chemistry)
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Library
Open Library is an online project intended to create "one web page for every book ever published". Created by Aaron Swartz, Brewster Kahle, Alexis Rossi, Anand Chitipothu, and Rebecca Malamud, Open Library is a project of the Internet Archive, a nonprofit organization. It has been funded in part by grants from the California State Library and the Kahle/Austin Foundation. Open Library provides online digital copies in multiple formats, created from images of many public domain, out-of-print, and in-print books. Book database and digital lending library Its book information is collected from the Library of Congress, other libraries, and Amazon.com, as well as from user contributions through a wiki-like interface. If books are available in digital form, a button labeled "Read" appears next to its catalog listing. Digital copies of the contents of each scanned book are distributed as encrypted e-books (created from images of scanned pages), audiobooks and streaming audio (created ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franciscus Mercurius Van Helmont
Franciscus Mercurius van Helmont (baptised 20 October 1614 – December 1698) was a Flemish alchemist and writer, the son of Jan Baptist van Helmont. He is now best known for his publication in the 1640s of his father's pioneer works on chemistry, which link the origins of the science to the study of alchemy. From his early work as a physician, he became a kabbalist and together with Henry More of the Cambridge Platonists he annotated Christian Knorr von Rosenroth's translations of kabbalist texts. Contacts and movement He led an itinerant life in wanderings in Europe, an adjective already applied to him by Anthony Ashley-Cooper, 3rd Earl of Shaftesbury in his 1711 ''Characteristicks of Men, Manners, Opinions, Times''. He self-identified as a "wandering eremite". Franciscus van Helmont had important groups of contacts in the Netherlands, where he knew Adam Boreel and Serrarius, and later in life, in 'the Lantern', the circle around the Rotterdam merchant Benjamin Furly t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isabelle Stengers
Isabelle Stengers (; ; born 1949) is a Belgian philosopher, noted for her work in the philosophy of science. Trained as a chemist, she has collaborated with Russian-Belgian chemist Ilya Prigogine and French philosopher/sociologist Bruno Latour among others, and has written widely on the history of science as well as philosophers such as Gilles Deleuze, Alfred North Whitehead, Donna Haraway, and Michel Serres. Biography Stengers is the daughter of the historian Jean Stengers. She studied chemistry, graduating with a degree in the subject from the Université libre de Bruxelles. Work Her research interests include the philosophy of science and the history of science. She holds her Professorship in the Philosophy of Science at the Université libre de Bruxelles and received the grand prize for philosophy from the Académie Française in 1993. Stengers has written on English philosopher Alfred North Whitehead; other work has included Continental philosophers such as Michel Serres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard University Press
Harvard University Press (HUP) is a publishing house established on January 13, 1913, as a division of Harvard University, and focused on academic publishing. It is a member of the Association of American University Presses. After the retirement of William P. Sisler in 2017, the university appointed as Director George Andreou. The press maintains offices in Cambridge, Massachusetts near Harvard Square, and in London, England. The press co-founded the distributor TriLiteral LLC with MIT Press and Yale University Press. TriLiteral was sold to LSC Communications in 2018. Notable authors published by HUP include Eudora Welty, Walter Benjamin, E. O. Wilson, John Rawls, Emily Dickinson, Stephen Jay Gould, Helen Vendler, Carol Gilligan, Amartya Sen, David Blight, Martha Nussbaum, and Thomas Piketty. The Display Room in Harvard Square, dedicated to selling HUP publications, closed on June 17, 2009. Related publishers, imprints, and series HUP owns the Belknap Press imp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guillaume-François Rouelle
Guillaume François Rouelle (, 15 September 1703 – 3 August 1770) was a French chemist and apothecary. In 1754 he introduced the concept of a base into chemistry as a substance which reacts with an acid to form a salt). He is known as ''l'Aîné'' (the elder) to distinguish him from his younger brother, Hilaire Rouelle, who was also a chemist and known as the discoverer of urea. He started a public course in his laboratory in 1738 where he taught many students among whom were Denis Diderot, Antoine-Laurent de Lavoisier, Joseph Proust and Antoine-Augustin Parmentier. He was elected a foreign member of the Royal Swedish Academy of Sciences in 1749. Why bases for neutral salts were called bases The modern meaning of the word "base" and its general introduction into the chemical vocabulary are usually attributed to the French chemist, Guillaume-François Rouelle (1703–1770), who used the term "Base" in a memoir on salts written in 1754 (see The Origin of the Term "Base" by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Sceptical Chymist
''The Sceptical Chymist: or Chymico-Physical Doubts & Paradoxes'' is the title of a book by Robert Boyle, published in London in 1661. In the form of a dialogue, the ''Sceptical Chymist'' presented Boyle's hypothesis that matter consisted of corpuscles and clusters of corpuscles in motion and that every phenomenon was the result of collisions of particles in motion. Boyle also objected to the definitions of elemental bodies propounded by Aristotle and by Paracelsus, instead defining elements as "perfectly unmingled bodies" (see below). For these reasons Robert Boyle has sometimes been called the founder of modern chemistry. Contents The first part of the book begins with 5 friends (Carneades the host and the Skeptic, Philoponus the Chymist, Themistius the Aristotelian, Eleutherius the impartial Judge, and an unnamed narrator) meeting in Carneades's garden and chatting about the constituents of mixed bodies. In part one, Carneades (Boyle) lays out four propositions to the gatheri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
